GB-SAR GB-SAR 시스템의 개발과 응용시스템의 개발과 응용

이훈열이훈열 , , 조성준조성준 , , 성낙훈성낙훈강원대학교 지구물리학과강원대학교 지구물리학과

한국지질자원연구원 지반안전연구부한국지질자원연구원 지반안전연구부

대한원격탐사학회 2007 춘계학술대회 3 월 30 일 대전 대덕컨벤션타운

ContentsContents

IntroductionIntroduction GB-SAR SystemGB-SAR System SAR Focusing and InterferometrySAR Focusing and Interferometry ApplicationsApplications ConclusionConclusion

IntroductionIntroduction GB-SAR: Ground-Based Synthetic Aperture RadarGB-SAR: Ground-Based Synthetic Aperture Radar

Synthetic Aperture RadarSynthetic Aperture Radar Imaging RadarImaging Radar Azimuth aperture synthesisAzimuth aperture synthesis

Ground-BasedGround-Based Fairly versatile system configurationFairly versatile system configuration

Multiple frequency (L, C, X, Ku, Ka, etc)Multiple frequency (L, C, X, Ku, Ka, etc) Full Polarization (VV, VH, HV, HH) Full Polarization (VV, VH, HV, HH)

Ultimate SAR focusingUltimate SAR focusing Zero Doppler centroid (stationary vehicle during Tx/Rx)Zero Doppler centroid (stationary vehicle during Tx/Rx) Accurate estimation of Doppler rate from geometry Accurate estimation of Doppler rate from geometry

Topography Mapping: Cross-Track InSAR or Delta-K InSARTopography Mapping: Cross-Track InSAR or Delta-K InSAR Surface Motion: Zero-baseline and short atmospheric path for Temporal Coherency, DInSAR and PSInSSurface Motion: Zero-baseline and short atmospheric path for Temporal Coherency, DInSAR and PSInS

ARAR Useful for new SAR concept designUseful for new SAR concept design

Previous WorksPrevious Works LISA (EU) for Avalanche and landslide monitoringLISA (EU) for Avalanche and landslide monitoring Other laboratory or field tests (UK, Japan)Other laboratory or field tests (UK, Japan)

GB-SAR SystemGB-SAR System

System ConfigurationSystem Configuration

T X R X O U TINM o t io nC o n t ro l

GP IB

T x V - p o lT x H - p o l

R x H - p o lR x V - p o l

SAR Focusing AlgorithmsSAR Focusing Algorithms

AlgorithmsAlgorithms AdvantangeAdvantange DisadvantageDisadvantage UsageUsage

Range-DopplerRange-Doppler or or ωω -k-k

Widely used Widely used for SARfor SAR

Memory Memory inefficiency inefficiency for partial-for partial-focusingfocusing

Near Range Near Range

(full-focusing)(full-focusing)

Deramp-FFTDeramp-FFTEfficient in Efficient in

memory and memory and CPU timeCPU time

Distortion in Distortion in near rangenear range

Far RangeFar Range

(partial-(partial-focusing)focusing)

Time DomainTime Domain Exact Exact everywhereeverywhere

Time Time consumingconsuming EverywhereEverywhere

GB-SAR ResolutionsGB-SAR Resolutions

(a) Full Focusing (b) Partial Focusing X

Rx

2

2aLx

Range resolution: B

cR

2

GB-InSAR ConfigurationGB-InSAR Configuration

DInSARDInSAR Cross-Track Cross-Track

InSARInSAR Delta-K InSARDelta-K InSAR Cross-Track and Cross-Track and

Delta-K InSARDelta-K InSAR

DInSAR with range change

Cross-Track InSAR

GB-SAR InterferometryGB-SAR Interferometry

ChangeChange Phase DifferencePhase Difference Range phase Range phase rampramp SensitivitySensitivity

DInSARDInSAR Range Range nonenone RangeRange

Cross-Cross-Track Track InSARInSAR

Vertical baseline Vertical baseline HeightHeight

Delta-K Delta-K InSARInSAR Frequency shift Frequency shift HeightHeight

Cross-Cross-Track Track and and Delta-K Delta-K InSARInSAR

andand HeightHeight

KIGAM Roof-Top TestKIGAM Roof-Top Test

T1T1 Range:

Center frequency=5.3GHz Bandwidth=200MHzSample=1601Power=33dBm (2W)

Azimuth: Scan length=5mStep=5cmSample=101

T2T2: Temporal baseline of : Temporal baseline of 20minutes (DInSAR)20minutes (DInSAR)

T3T3: Spatial baseline of -30cm : Spatial baseline of -30cm vertical (InSAR DEM)vertical (InSAR DEM)

T4T4: Frequency shift of -10MHz : Frequency shift of -10MHz (Delta-K InSAR)(Delta-K InSAR)

Image AreaImage Area

VVVV

T1

VHVH

T1

HHHH

T1

DInSAR (T2-T1)DInSAR (T2-T1)

VV

Cross-Track InSAR (T3-T2)Cross-Track InSAR (T3-T2)

VV

Delta-K InSAR (T4-T3)Delta-K InSAR (T4-T3)

VVVV

Cross-Track and Delta-K InSAR Cross-Track and Delta-K InSAR (T4-T2)(T4-T2)

VVVVVV

Automatic AcquisitionAutomatic Acquisition with 2cm Step, 2007. 3. 19 7:22pm- 4:20am, A1~A9with 2cm Step, 2007. 3. 19 7:22pm- 4:20am, A1~A9

HHVV

Phase ErrorsPhase Errors

Ideal CaseA6-A5, HH

Azimuth scan shift of 2cm. A9-A1, HH

Range System Shift of 2mm

ConclusionConclusion We made a SAR system.We made a SAR system. A GB-SAR system was developed, tested, and waiting for applications.A GB-SAR system was developed, tested, and waiting for applications. Optimal GB-SAR focusing algorithms were tested.Optimal GB-SAR focusing algorithms were tested. Cross-Track and Delta-K InSAR were tested.Cross-Track and Delta-K InSAR were tested. DInSAR or PSInSAR were tested: Phase stability of 1DInSAR or PSInSAR were tested: Phase stability of 1° (0.1mm range) was ac° (0.1mm range) was ac

hieved for several hours for stable reflectors, rendering phase change of 1hieved for several hours for stable reflectors, rendering phase change of 10 ° meaningful (1mm range accuracy for DInSAR).0 ° meaningful (1mm range accuracy for DInSAR).

GB-SAR can be used for various applications such as:GB-SAR can be used for various applications such as: Safety monitoring of natural or anthropogenic structuresSafety monitoring of natural or anthropogenic structures Microwave backscattering properties of targetMicrowave backscattering properties of target New SAR system concept designNew SAR system concept design

More robust GB-SAR system optimized to a specific application will be develMore robust GB-SAR system optimized to a specific application will be developed. oped.

Thank YouThank You